Received: from maia.hub.org (maia-2.hub.org [200.46.204.251]) by mail.postgresql.org (Postfix) with ESMTP id 6CB7B1337A5D for ; Wed, 6 Apr 2011 21:23:12 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.251]) (amavisd-maia, port 10024) with ESMTP id 99959-03 for ; Thu, 7 Apr 2011 00:22:52 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from EXHUB018-4.exch018.msoutlookonline.net (exhub018-4.exch018.msoutlookonline.net [64.78.17.19]) by mail.postgresql.org (Postfix) with ESMTP id 02F821337C06 for ; Wed, 6 Apr 2011 21:22:02 -0300 (ADT) Received: from EXVMBX018-1.exch018.msoutlookonline.net ([64.78.17.47]) by EXHUB018-4.exch018.msoutlookonline.net ([64.78.17.19]) with mapi; Wed, 6 Apr 2011 17:22:03 -0700 From: Scott Carey To: "gnuoytr@rcn.com" , "pgsql-performance@postgresql.org" Date: Wed, 6 Apr 2011 17:22:01 -0700 Subject: Re: Intel SSDs that may not suck Thread-Topic: [PERFORM] Intel SSDs that may not suck Thread-Index: Acv0udFXRrTaaSaMRWGixoZYooQWhQ== Message-ID: In-Reply-To: <201104062303.060548@ms14.lnh.mail.rcn.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Microsoft-MacOutlook/14.2.0.101115 acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.9 tagged_above=-10 required=5 tests=BAYES_00=-1.9 X-Spam-Level: X-Archive-Number: 201104/60 X-Sequence-Number: 43122 On 4/6/11 4:03 PM, "gnuoytr@rcn.com" wrote: >Not for user data, only controller data. > False. I used to think so, but there is volatile write cache for user data -- its on the 256K chip SRAM not the DRAM though. Simple power failure tests demonstrate that you lose data with these drives unless you disable the cache. Disabling the cache roughly drops write performance by a factor of 3 to 4 on G1 drives and significantly hurts wear-leveling and longevity (I haven't tried G2's). > > >---- Original message ---- >>Date: Wed, 6 Apr 2011 14:11:10 -0700 (PDT) >>From: pgsql-performance-owner@postgresql.org (on behalf of Andy >>) >>Subject: Re: [PERFORM] Intel SSDs that may not suck >>To: Merlin Moncure ,Scott Carey >> >>Cc: "pgsql-performance@postgresql.org" >>,Greg Smith >> >> >>--- On Wed, 4/6/11, Scott Carey wrote: >> >> >>> I could care less about the 'fast' sandforce drives. >>> They fail at a high >>> rate and the performance improvement is BECAUSE they are >>> using a large, >>> volatile write cache. >> >>The G1 and G2 Intel MLC also use volatile write cache, just like most >>SandForce drives do. >> >>--=20 >>Sent via pgsql-performance mailing list >>(pgsql-performance@postgresql.org) >>To make changes to your subscription: >>http://www.postgresql.org/mailpref/pgsql-performance > >--=20 >Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) >To make changes to your subscription: >http://www.postgresql.org/mailpref/pgsql-performance